Punditsfling around the term pivot rather cavalierly; seldom does anyone define what the pivot is. Well, then, what is it? Let’s ask the strategist Woody Allen, who counsels that eighty percent of life is showing up. Quite so! If the United States pivots to a given region, it must concentrate not just policy attention but diplomatic, economic, and military resources on that region. It has to show up in the Western Pacific and Indian Ocean—and stay there. History is unkind to powers that speak loudly yet carry small sticks.

As Admiral J. C. Wylie observes, the element where warriors operate colors how they see the world. Airmen, for instance, view air power as the go-to instrument for achieving operational and strategic goals. I am a mariner and see the world through a seaman’s eyes. In maritime terms, the pivot is about preserving the United States’ capacity to project sea power (including its aerial and ground components) onto East and South Asian shores, preferably in concert with allied armed forces. Without allies to anchor the American presence, no pivot can long endure. Hence the prominent place Japan and other partners occupy in U.S. grand strategy.

Thus has it been since the Spanish-American War of 1898, when the United States wrested a modest Caribbean and Pacific empire from Spain. Before that the New World was an object on which European great powers acted. By World War II, however, the pattern of geopolitical influence had largely reversed. Power radiated from North America toward Eurasia. This was America’s first pivot, to the rimlands of Western Europe and East Asia. Keeping a single hegemon or hostile alliance from dominating Eurasia—and thereby constituting a threat to the Western Hemisphere—has been central to U.S. grand strategy since those halcyon days.

Now as then, the determinants of the pivot’s success will be strategic mass and strategic maneuver, meaning the U.S. armed forces’ capacity to amass superior might in far-flung—and increasingly contested—theaters. The U.S. military only plays away games. Factoids about the size of the U.S. Navy—that it’s bigger than the next thirteen navies combined, or smaller than it has been since 1917—say little about whether Washington can execute a Woody Allen strategy in the Indo-Pacific.

How well U.S. and allied sea power matches up with real opponents in today’s setting comprises the true standard by which to gauge the pivot’s success.